Strange external monitor behavior

[sturg]

So I want to use my new, M1 Pro, MBP with an external monitor. And I want to use it with the computer lid/screen closed, in clamshell mode. So I hooked up my brand new LG monitor today, and it works fine as long as I have the computer charging cable plugged into the computer. As soon as I disconnect the charger cable from the computer the monitor screen goes black and says no signal. I figured that there's gotta be a setting on monitor or on the computer that I can adjust to change this behavior.
First I called LG, but they said to call Apple, which I did. The senior tech advisor from Apple told me that there is nothing to change on the laptop and this is EXACTLY how the computer and monitor is supposed to behave. He said that there is nothing to worry about as far as having the computer plugged and constantly charging 24/7. He said no harm will come to the battery or the charger or the computer from doing this. He said the reason that the monitor turns off when disconnected is because the computer does not have enough power to run the monitor without being plugged in......BUT isn't that what the power plug on the MONITOR is for?? To power the monitor?
What have been your experiences with this issue? Does this seems right?
I just can't get used to leaving that charger plugged in all the time.
Any advice is much appreciated. Ty.

 

[Jim Lahey]

Can’t help directly with your problem, but look into AlDente Pro. The single most crucial app for anyone using a MacBook that’s almost always running on mains power. It lets you set a maximum charge level, has quite a lot of customisation, and includes options to inhibit charging when sleeping or even when powered off. My MacBook Pro is used in clamshell mode 24/7 on outlet power with the battery ‘sailing’ between 45-50%. I then run the inbuilt calibration mode once a month just to give it a workout.

 

[Jim Lahey]

By the way, when the monitor loses signal after killing the Mac's power, you would probably find that opening the lid will force it to reconnect and then stay connected when you close it again. Sounds odd but I have similar behaviour with my setup. But all that aside, I highly recommend AlDente Pro regardless.